This subproject is one of many research subprojects utilizing the resources provided by a Center grant funded by NIH/NCRR. The subproject and investigator (PI) may have received primary funding from another NIH source, and thus could be represented in other CRISP entries. The institution listed is for the Center, which is not necessarily the institution for the investigator. Our proposed studies intend to systematically investigate neuronal and vascular mechanisms of sympathetic neurotransmitter storage, release, and receptor binding in human skin. Also, we intend to supplement BH4 and ascorbate exogenously in aged subjects to potentially ameliorate vasoconstrictor function. The proposed studies will be pilot work used for an upcoming competitive NIH R01 renewal.